Photoproduction of the K⁺ K^-(1750)

Thesis/Dissertation · Wed Jan 01 00:00:00 EST 2003

DOI:https://doi.org/10.2172/15020140· OSTI ID:15020140

Mitchell, Ryan Edward ^[1]

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1. Univ. of Tennessee, Knoxville, TN (United States)

While photoproduction has often been advertised as an important environment in which to study light meson spectroscopy, solid experimental results are sparse. In fact, beyond the relatively straightforward photoproduction of the ρ, ω, and Ψ mesons, the few results of exclusive photoproduction that do exist are poorly understood, and several, perhaps, have even been misinterpreted. After extensively reviewing the sometimes tenuous history of the exclusive photoproduction of the ''ρ¹(1600)'', the ''ωπ⁰(1250)'', the ''ω(1650)'', and the ''K⁺K^-(1750)'', new results from the E831/FOCUS photoproduction experiment at Fermilab are presented which address the interpretation of the K⁺K^-(1750). This enhancement in low-p_T K⁺K^- pairs at a mass near 1750 MeV/c² has been observed by several previous photoproduction experiments, but, despite several apparent inconsistencies, it has always been interpreted as the J^PC = 1^-- ρ(1680) meson. With nearly two orders of magnitude more events than any previous observation of the K⁺K^-(1750), and based on precise measurements of its mass and width, and its absence from the K*K final state, the FOCUS data can finally render this interpretation implausible. In addition, several steps have been taken towards establishing a new interpretation. Based on limited angular analyses of its decay and the beam energy dependence of its production, they argue that, in the absence of any wild interference scenarios, the K⁺K^-(1750) has J^PC ≠ 1^--, and, in fact, the most likely assignment appears to be 2⁺⁺. It is hoped that this work can help set the stage for future reevaluations and new insights in photoproduction.

• Research Organization: Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76CH03000
• OSTI ID: 15020140
• Report Number(s): FERMILAB-THESIS-2002-29; TRN: US0605295
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
DECAY
ENERGY DEPENDENCE
FERMILAB
MESON SPECTROSCOPY
MESONS
PHOTOPRODUCTION
PRODUCTION
Experiment-HEP